Telephone coupling device



Nov. 21, 1939.

J. C. BARN TELEPHONE COUPLING DEVICE Nov. 2l, 1939. '.J. c. BARNESTELEPHONE COUPLING DEVICE Filed Nov. 25, 19256 2 Sheets-Sheet' 2INVENTOR JAMES c. BARN'ES FIG. 5

FIG. 6

ATTORNEY Patented Nov. 21, 1939 UiTEDY STATES ceri.

Associated Press, tion of New York New York, N. Y., acorpora-Application November 25, 1936, Serial No. 112,686

s claims.

This invention relates to a telephone coupling device.

An object of the invention is to provide a simple and inexpensiveapparatus for connecting pic- 5 ture transmission systems and the liketo standard telephone equipment.

vAnother object of the invention is the provision of a light andinexpensive device of small size by which portable picture transmissionapparatus or other apparatus operating at audio frequency may be quicklyand conveniently coupled to a telephone circuit Without the necessity ofdisturbing the telephone Wiring or equipment.

Apparatus for a similar purpose has been proposed by which connection ismade inductively, or otherwise, at the ringer box, but such .equipmentis more bulky than the present invention and consequently less suitedfor use for portable Z apparatus; and very often ringer boxes arelocated in inaccessible places making it inconvenient to attach suchequipment.

It has been proposed also,A to use a current generated by a vibratingdiaphragm controlled Afrom a telephone receiver, but this arrangement isnot as compact as desired for portable equipment, and furthermore, atelephone controlled diaphragm introduces unnecessary distortion into acircuit.

3 The invention Will now be described with the aid of the accompanyingdrawings of which Figure v1 is a schematic diagram showingthe magnet ofa telephone receiver and the present invention with the receiverdiaphragm between 35 the respective magnets.

Figure 2 is a similar diagram except that the telephone diaphragm isomitted for maximum energy transfer.

Figure 3 illustrates one method of rotatably coupling the presentinvention to the shell` of a telephone receiver.

Figures 4 and 5 show a modification of the invention which may beattached to a receiver without removing the receiver cap, Figure 5 beinga section taken through 5-5 of Figure 4.

Figure 6 shows a brace for the polepieces made from a piece of Bakelite.

Referring now to the drawings: The reference character I indicates aconventional telephone receiver permanent magnet having windings 2connected to outgoing circuits 3 and 4. The Wiring details oi theinstrument and ringer box are omitted as unnecessary, but it will beunderstood that the receiver is connected to an outgoing line.

The square 5 indicates a picture transmission (Cl. 17e-2)' apparatus orother frequency controlled equipment located at adistant point. In thepresent instance the letter T indicates a picture transmitter which isconnected through lines 6 and I to lines 3 and 4'. 5

The reference character I@ indicates alamihated core cr other magneticcircuit Whose ends are separated by the same' distance as that of thepolepieces of the receiver magnet I. The core if laminatedmay bemagnetized by a per- 10 man-ent magnet, or consist of laminations alone,or it may be a permanent magnet as in the case of certain types oftelephone receivers.

Windings II and I2 on core ID are connected to each other in seriesaiding, While the exter- 15 nal terminals ofthe coils are connectedrespectivelyto lines I3 and I4 Which in turn are connected `to lines I5and I6 extending from a picture receiving set, indicateddiagrammatically by the square I'I and the letter R. In this em- 20bcdim'ent the polepieces of core ID and preferably those of magnet` Irest against diaphragm I8 of the receiver.

Figure 2 shcwsa preferred embodiment of the invention differing onlyfrom that described 25 above in that the polepieces cfboth magnets arein Contact with each other.' In thiscase, the terminal. equip-ment isreversed from that or Figure land 5 is the receiver and Il vthe trans*mitter.

The assemblyk including core Il) and its coils are ypreferably. mountedin a casing, somewhat similar 'to the Well-known Watch case type of earphone indicated in Figure 3 by the reference character I9, which is thesame size at the edge as a telephone receiver. A convenient method ofcoupling the apparatus to a receiver is by means of a ring 29 suitablythreaded at 2| to screw over the cap threads 22 of a receiver 23, Whilethe opposite end of ring 20 has an inside 40 ange 24 which engages anannular ring 25 at the edge of `casing I9, which when the ring istightened on the receiver shell will hold the respective magnetstogether, `or in a fixed position in respect to each other. Any Wellknown means may be employed, if required, to adjustthe core I0 in alongitudinal direction.

Figures 4 and 5 show another modification of the invention which may beattached tothe receiver of a telephone Without removing the receiver capor otherwise disturbing the apparatus. This modification makes itpossible for persons lacking'the mechanical skill to unscreW and replacea telephone receiver cap to connectv an audio frequency device to atelephone system.

This modiiication is particularly useful in connection with telephonenews broadcasts now furnished to pool-rooms, clubs and the like ofsporting events, in which the line signals are received via telephoneand amplified and reproduced through suitable loud speaking apparatus.

In Figures 4 and 5 a conventional telephone receiver cap 3|) is shownhaving a circular central opening 3|, into which snugly fits polepieces32, of a magnet I having windings II and I2 similar to those previouslydescribed.

The outer part of the polepieces in this embodi# ment, are preferablycurved to t the circular opening 3| in the center of the receiver cap asshown in Figure 4.

The magnet I0 is preferably mounted in a shell 36 provided with one ormore pairs of spring clips 31 which engage the underside of the receivercap, rotatably securing the shell 36 thereto; the clips, shell andpolepieces being of such dimensions that with the device in place,polepieces 32 buckle diaphragm I8 of the receiver slightly, pressing itagainst polepieces 40 of the receiver and preventing the diaphragm fromvibrating.

When this embodiment of the invention is clipped tca receiver shell, itis not necessary to remove the receiver cap and diaphragm to locate thepolepieces, as all that is required, once the device is in place is torotate it in respect to the receiver shell until the desired signallevel is reached. The respective poles are coaxial with the maximumsignal transfer.

Operation The device operates as follows:

Assuming that the apparatus indicated at I1 is for transmitting picturesaccording to Well known practice, then the signal current to betransmitted sets up a magnetomotive force in core I0. In the case ofFigures l, 4, and 5, the magnet circuit is partially through diaphragmI8 and the permanent magnet I of the receiver.

The flux produced by the signal voltage will divide between the twomagnetic circuits. The part passing through the telephone receiverpolepieces induces a voltage in the receiver coils 2 which will go outto lines 3 and 4 to the distant receiving apparatus 5. Likewise, if thereceiving and transmitting apparatus were transposed, the incomingsignal current Would induce a current in windings II and I2, which inthis case would be connected to receiving apparatus as indicated inFigure 1.

For maximum transfer of energy, the polepieces of magnet I and core Illshould be coaxial. Figure 2 shows the most efficient arrangement as thepolepieces are in contact and there is no division of the magneticcircuit through a diaphragm. If desired, the signal level may be con.-trolled by rotating the magnets I and I0 in respect to each other, aspreviously stated.

, yW hat is claimed is:

1. In a device of the character described, an

electric circuit and a telephone system including receivers; means toconnect said circuit to said telephone system, which includes a pair ofmagnets connected tosaid circuit, polepieces for magnets shaped to i'ltthe opening in a receiver cap, and means for securing the firstmentioned means to a telephone receiver so that said polepieces extendthrough the opening in said receiver cap and engage the diaphragm ofsaid receiver.

2. In a device of the character described, an electric circuit and atelephone system, including telephone receivers; means to connect saidcircuit to said telephone system lwhich includes a pair of magnetsconnected to said circuit, polepieces for said magnets shaped to fit theopening in a receiver cap, and means for securing the first mentionedmeans to a telephone receiver so that said polepieces extend through theopening in said receiver cap and engage the diaphragm of said receiverpressing it against the receiver polepieces and thereby preventing thediaphragm from vibrating.

3. In a device of the character described, an electric circuit and atelephone system including telephone receivers; means to connect saidcircuit to said telephone system which includes a pair of magnetsconnected to said circuit, polepieces for said magnets shaped to t theopening in a receiver cap, and means for rotatably securing the firstmentioned means to a telephone receiver so that said polepieces extendthrough the opening in said receivercap and engage the diaphragm of saidreceiver pressing it against the receiver polepieces and therebypreventing the diaphragm from vibrating, means for adjusting the signalcurrent which comprises rotating said magnets in respect to each other.

JAMES C. BARNES.

